class Mime::Type

Encapsulates the notion of a MIME type. Can be used at render time, for example, with:

class PostsController < ActionController::Base
  def show
    @post = Post.find(params[:id])

    respond_to do |format|
      format.html
      format.ics { render body: @post.to_ics, mime_type: Mime::Type.lookup("text/calendar")  }
      format.xml { render xml: @post }
    end
  end
end